Monomer and polymer adhesives/sealants are used in both industrial (including household) and medical/surgical applications. Included among these adhesives or sealants are cyanoacrylates monomers and polymers resulting therefrom. Since the discovery of the adhesive/sealant properties of such monomers and polymers, they have found wide use due to the speed with which they cure, the strength of the resulting bond formed, and their relative ease of use. These characteristics have made α-cyanoacrylate compositions the primary choice for numerous adhesive applications such as bonding plastics, rubbers, glass, metals, wood, and, more recently, medical, biological or living tissues.
Medical and surgical applications of α-cyanoacrylate compositions include their use as alternates or adjuncts to surgical sutures, meshes and staples or other medical devices in wound closure, as well as for covering and protecting surface wounds such as lacerations, abrasions, burns, stomatitis, sores, and other surface wounds. When an α-cyanoacrylate composition is applied, it is usually applied in its monomeric form, and the resultant polymer creates the desired adhesive bond or sealant strength.
At standard temperatures, the monomeric α-cyanoacrylate may run when applied to surfaces. As a result, the α-cyanoacrylate adhesive may spread into a wound or along a surface to which it has been applied to areas that do not require an adhesive and that may be adversely affected by an adhesive. Therefore, it is desirable to control the viscosity of the monomeric α-cyanoacrylate composition in order to prevent escape of the adhesive from the area of application. In order to reduce run-off or achieve a suitably viscous adhesive, a thickening or viscosity modifying agent may be added to a monomeric α-cyanoacrylate composition.
Polymerizable α-cyanoacrylate monomers and compositions comprising such monomers are disclosed in U.S. Pat. No. 5,328,687. Further, the use of polymers as thickening agents for α-cyanoacrylate monomers and compositions is disclosed in U.S. Pat. No. 6,433,096. Each of the above documents is incorporated by reference herein in its entirety.
For some medical applications, an absorbable thickening or viscosity modifying agent provides benefits over a non-absorbable thickening or viscosity modifying agent. For example, it is desirable to have a monomer-based internal adhesive or sealant composition that polymerizes in vivo, where the monomer, the composition thereof, and the resultant polymer are biocompatible. It is also desirable to use an adhesive or sealant composition that fills internal cavities and voids, penetrating and conforming to the interstices and pores of the tissue, prior to curing or setting. Finally, it is desirable that the resultant polymer also be biodegradable, so that the degradation products are completely eliminated from the human body as waste products.
Therefore, there is a need for an absorbable and biocompatible viscosity modifying agent for α-cyanoacrylate compositions that exhibits controlled viscosity and absorbability sufficient for medical applications and produces a polymer adhesive/sealant that may also be biodegradable.
While it is desirable to have an adhesive that is biodegradable, achieving such biodegradability should not adversely affect other desirable properties of the adhesive, e.g., stability. In order for an adhesive to be a commercially viable product, it is preferred that the monomeric form of the adhesive have a shelf life of at least one year at standard, non-refrigerated, temperatures.
Therefore, there is a need for an α-cyanoacrylate adhesive composition that is absorbable and biocompatible and also stable enough to be commercially viable.